U.S. patent number 4,939,705 [Application Number 07/275,294] was granted by the patent office on 1990-07-03 for drug dispensing event detector.
This patent grant is currently assigned to Aprex Corporation. Invention is credited to Richard G. Hamilton, David M. Liu.
United States Patent |
4,939,705 |
Hamilton , et al. |
July 3, 1990 |
Drug dispensing event detector
Abstract
A device for detecting the dispensing of drugs from a container
in a way which eliminates false detection events due to mishandling
of the container is disclosed. The device includes a container
which may be opened and closed. It also contains a means for
detecting the opening and separately detecting the closing of the
container as well as means for measuring the time between these
events and comparing this elapsed time to a predetermined standard
indicative of drug dispensing event. The times of proper drug
dispensing events are stored in the device for use by the health
care professional following the patient's drug dosing compliance.
Other opening and closing intervals which fall outside this time
range give rise to an alternative response. They may be recorded
with a notation of their probable error or they may be disregarded.
In other aspects, the invention provides a preferred physical
configuration for the electronic components of the device and a
preferred means for accessing the data stored in the device.
Inventors: |
Hamilton; Richard G. (Fremont,
CA), Liu; David M. (Los Altos, CA) |
Assignee: |
Aprex Corporation (Fremont,
CA)
|
Family
ID: |
23051677 |
Appl.
No.: |
07/275,294 |
Filed: |
November 23, 1988 |
Current U.S.
Class: |
368/10; 368/108;
221/2 |
Current CPC
Class: |
A61J
7/0436 (20150501); A61J 2200/30 (20130101); A61J
7/0418 (20150501) |
Current International
Class: |
A61J
7/00 (20060101); A61J 7/04 (20060101); G04B
047/00 (); G07F 011/00 () |
Field of
Search: |
;368/10,107-113
;221/2,3,15 ;340/309.15,309.4 ;364/569 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Miska; Vit W.
Attorney, Agent or Firm: Irell & Manella
Claims
What is claimed is:
1. A device for detecting the dispensing of drug from a container
comprising
a container having an openable and reclosable dispensing
aperture,
means capable of generating a first electrical signal in response
to the opening of the openable aperture and a second electrical
signal in response to the reclosing of the aperture,
means for measuring the elapsed time between the first electrical
signal and the second electrical signal,
means for comparing the elapsed time with a predetermined
accept/reject time range and determining if the elapsed time falls
within the accept range, and
means for recording each time an elapsed time within the accept
range is determined.
2. The device of claim 1 wherein the predetermined accept/reject
time range is a time range having a minimum boundary of about 0.5
seconds.
3. The device of claim 2 wherein the recording is noted as a valid
dispensing of drug from the container.
4. The device of claim 1 additionally comprising means for
measuring a second elapsed time between the second electrical
signal and the next subsequent first electrical signal
means for comparing the second elapsed time with a second
predetermined accept/reject time range and determining if the
elapsed time falls within that second accept range, and
means for recording each time an elapsed time within the second
accept range is determined.
5. The device of claim 4 wherein the second predetermined
accept/reject time range is a time range having a minimum boundary
of about 2 seconds.
6. The device of claim 5 wherein the recording is noted as a valid
closing of the container.
7. The device of claim 4 additionally comprising means for
recording openings or closings of the container which fall outside
the accept range.
8. The device of claim 4 additionally comprising means for alerting
the patient when the elapsed time is larger than the accept
range.
9. The device of claim 4 additionally comprising means for
informing the patient's health care professional when an elapsed
time outside the accept ranges has been detected.
Description
BACKGROUND OF THE INVENTION
2. Field of the Invention
This invention relates to a device for monitoring the dispensing of
medication to patients. More particularly it relates to a system
for accurately detecting drug dispensing events.
2. Description of the Prior Art
A variety of devices and methods have been described for
controlling, noting, and keeping track of dispensation of medicines
to patients. These devices range from simple mechanical checklist
systems, through pill containers equipped with alarm clocks and the
like and pill containers having timer-controlled latching devices
which regulate the patient's access to medication. Some typical
examples of these devices include the timed medication dispenser
described by Roy J. Machamer in U.S. Pat. No. 4,382,688 which shows
a medical dispenser having an electronic reminder to take the
medication it contains. In this device the electronic reminder is
disabled when the user takes the medication. In U.S. Pat. No.
4,448,541, Jonathan D. Wirtschafter describes a magnetically
responsive switch device which is activated when a medication
dispenser is opened so as to give an indication of the drug
dispensing event. U.S. Pat. No. 4,367,955 of Donald H. Ballew shows
a combined timer and container for dispensing medications wherein
the container and its lid coact to initiate the timer cycle upon
interengagement of the cap and container. U.S. Pat. No. 4,034,757
of Glover shows a device having two switches, each of which must be
activated simultaneously to register a drug delivery event.
The foregoing patents are merely representative. Other background
patents relating to medication dispensers include for example U.S.
Pat. Nos. 3,369,697 of Glucksman et al.; 3,395,829 of Cogdell et
al.; 3,651,984 of Redenback; 3,722,739 of Blumberg; 3,762,601 of
McLaughlin; 3,815,780 of Bauer; 3,911,856 of Ewing; 3,917,045 of
Williams; 3,968,900 of Stambuk; 3,998,356 of Christensen; 4,207,992
of Brown; 4,223,801 of Carlson; 4,258,354 of Carmon et al.;
4,275,384 of Hicks et al.; 4,360,125 of Martindale et al.;
4,361,408 of Wirtschafter; 4,382,688 of Machamer; 4,419,016 of
Zoltan; 4,448,541 Wirtschafter; 4,473,884 of Behl; 4,483,626 pof
Nobel; 4,490,711 of Johnston; 4,504,153 of Schollmeyer et al. and
4,526,474 of Simon.
In the case of devices with which it is desired to monitor access
to a multidose drug container it is of importance to be able to
identify true access events and distinguish them from false events.
A true event would include opening the container, removing a pill
or other medicament and then closing the container. A false event
could include leaving the container open and repeatedly removing
pills or, in the case of the not-sure-handed, repeated attempts at
reinstalling the cap after a single removal of a drug or dropping
the closed container, thereby actuating the open-close switch by
means of the force of impact.
It is an object of this invention to provide a detection system
which will be capable of identifying true drug removal events and
discriminating them from these false events.
It is important that a device capable of electronically identifying
and recording drug dosing information be constructed in a manner
which is sturdy and reliable. It is also important that the
construction be such as to minimize even inadvertent contact
between the medication contained in the device and the various
electronic elements which note and record the dosing information.
This avoids contamination of the drug by contact with the
electronic component, on the one hand, and interference with the
proper functioning of the electronics by contact with the drug, on
the other. The construction should also minimize cost and
advantageously permit reuse of expensive electronic components. To
these ends, it is a further object of this invention to provide a
device for measuring and recording drug dosing information which
physically separates the majority of the electronic components from
the drug storage chamber. It is also an object of this invention to
provide a device in which major electronic components can be
recycled.
STATEMENT OF THE INVENTION
In accord with the present invention, a device is provided which is
capable of discriminating between true and false drug dispensing
events. This device includes a drug container having an openable
and reclosable cap, lid or other similar dispensing aperture. The
container is equipped with a detector which generates a first
electrical signal in response to the opening of the dispensing
aperture and a second electrical signal in response to the
reclosing of the aperture. The device additionally includes a
timing mechanism which measures the time elapsed between the first
electrical signal and the second electrical signal. The elapsed
time is then compared to a predetermined accept/reject standard.
Times shorter than the accepted range, and thus indicative of
fumbling with the cap or an impact event, are rejected. In
preferred embodiments times longer than the accepted range and thus
indicative of an open container can also be rejected. In other
embodiments the device can measure the time between a closing and
the next opening and compare that period to a standard to validate
a drug dispensing event. A time meeting the preset criteria, such
as falling within the desired range, is considered to be a good
indication of a true drug-dispensing event. The device further
includes a system for using these indications of true
drug-dispensing events. This system of use can include a memory for
storing the number of such events. It can also include a
timekeeping mechanism which can provide and record the time and
date each time an elapsed time within the accept range is
determined. The information so determined and stored can be
accessed by the pharmacist, physician or other health care
professional as needed to verify compliance with dosing regimens,
to give an indication of the patient's condition, or the like. In
alternative embodiments, the determination that an elapsed time has
fallen outside the accept range can be used to activate an alarm,
to deliver a message to the patient or to the patient's health care
professional or to alter the delivery pattern of drugs from the
device such as by disabling the ability of the device to deliver
drug or the like.
In other aspects, this invention provides an improved construction
for an electronic medication monitor. In this preferred
construction, the electronics are present in a removable cap for a
medication container. In this construction all the electronics,
except for a switch, are isolated from the drug container so that
contamination between the electronics and the drug is avoided. In
other aspects, the electronics are positioned so that expensive
components may be removed and recycled. In yet a further aspect,
the device of this invention can include an electronic access port
through which data and program information is loaded and off-loaded
wherein this access port is in the form of a plurality of
electrically conductive pads which are accessed by spring-loaded
pins in a suitable probe.
DETAILED DESCRIPTION OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be further described with reference
being made to the accompanying drawings in which:
FIG. 1 is a perspective elevational view of a pill container
incorporating the present invention.
FIG. 2 is a cutaway of the device shown in FIG. 1.
FIG. 3 is a simple circuit diagram of one form of electronics
usable as part of the present invention.
FIG. 4 is an exploded cross-sectional side view of a cap for a drug
container, which cap contains the electronics necessary for noting
and recording drug delivery in accord with this invention.
FIG. 5 is a cross-sectional side view of the cap of FIG. 4 in
unexploded format.
FIG. 6 is a top view of the cap of FIG. 4.
FIG. 7 is a cross-sectional view of a probe pin useful for making
electrical contact with the electronic circuitry of the cap of FIG.
4 for data output or program input.
Description of Preferred Embodiments
Turning first to the drawings, In FIGS. 1 and 2, a drug container
10 is illustrated as including a pill vial 11 and
removable/reclosable cap 12. Cap 12 serves as a drug access port
and in the embodiment shown additionally includes an optional
optical readout 13 which can be used to display messages, signals
or the like. Container 10 can take on a variety of configurations.
It can be a dry pill container, as shown, a fluid drug container
with a removable or openable cap, an aerosol with its dispensing
nozzle carried under a removable/replaceable cover, or the like. In
any embodiment, device 10 includes means for noting opening and
closing of the drug access port. This can take the form of switch
21 which is physically engaged when the top 12 is placed on vial 11
and which is disengaged when it is removed. Of course, other
functionally equivalent magnet switches or the like could be used
so long as they give an accurate indication of the opening and the
closing of the drug container. The output of switch 21 is fed to
circuit board 22. Latching tabs 23 are used to fasten the top to
the vial.
The signal so generated by switch 21 is fed into an electronic
circuit such as shown in FIG. 3. In FIG. 3, 3-volt power is
supplied by lithium battery 30 to a variety of locations in the
circuit, as noted in legend VCC. The circuit employs a general
purpose microprocessor 32. A 32 kHz clock crystal frequency is fed
to pins X1 and X2 of microprocessor 32.
An active analog filter, constructed to set the pair of times which
validate an opening, is coupled to pin P60 of microprocessor 32.
This filter functions as follows--when the cap is removed, switch
21 is closed. This sends current through resistor 34 to capacitor
36. This resistor and capacitor are matched so that it takes about
0.5 seconds for the capacitor to charge to a threshold voltage
which can be read by the microprocessor. If the switch was not
closed for at least this period, as would be the case with an
instantaneous closing, such as if the device were dropped, an
adequate charge to indicate cap removal would not be generated, and
the microprocessor would not be signaled that the cap had been
removed. As will be appreciated, resistor 34 and capacitor 36 can
be altered in value to give other time constants, if desired.
After a "cap off" signal has been sent to the microprocessor, pin
P60 remains above the threshold voltage. When the cap is replaced,
eliminating the voltage source through resistor 34, capacitor 36 is
drained at a set rate through resistor 38 to ground 40. The value
of resistor 38 is selected in this particular case so that the
voltage drains past the threshold voltage. In the circuit shown,
this takes about 2 seconds. At that time, pin P60 notes that the
cap has been replaced. Thus, the device provides that a valid cap
closing occurs after 2 seconds. If the cap were to be jiggled back
open, this would cause current to flow through switch 21 and
resistor 34 to maintain pin P60 at a "cap open" voltage.
Returning to microprocessor 32, it is a general purpose which
contains an internal clock function. It also contains a small
amount of RAM and about 2K of 8-bit ROM. This contains custom code
which is used to communicate with RAM memory 42 drug delivery
information generated by the actuation of switch 21 and filtered
with the validation circuit is stored in RAM 42 together with time
information supplied by microprocessor 32. This information is
accessible through data point 44. It may be used by the health care
professional to determine dosage times so as to validate correct
dosing or to determine incorrect dosing.
The time interval between opening and reclosing the top of drug
container 10 has been shown to be measured and compared to a
predetermined standard. In the case shown, if the time between the
two events is shorter than about 0.5 seconds, the system logic
determines that in fact the top was not removed and a drug dose was
not dispensed simply because that time was too short. This event
would be classed as an inadvertent or error signal. No indication
of drug dosing would be noted. Similarly, if the time interval
between the closing and the subsequent opening is too short, for
example, less than about 2 seconds, the device will not register
the event as a true closing of the device and instead record the
event as a mere fumbling with the cap or the like. The device can
additionally be equipped to compare the interval between a valid
opening and valid closing an provide an indication as to whether or
not this interval is consistent with a single dosing or not. Too
long an interval would suggest that the device was left open for an
extended period and that possibly multiple doses were taken. In a
variation, the device may contain information indicating the usual
time between successive doses. If the time period between a valid
opening and a valid closing far exceeded the normal period of a few
seconds, but rather corresponded to the period between successive
doses, the device could be equipped to indicate the logical
conclusion that the device was opened, a dose taken, and the device
not reclosed until a subsequent time when a second dose was
taken.
Correct drug dispensing events, that is a proper opening and a
proper closing separated in time by a proper interval can be stored
into a readable memory for use by the health care professional to
verify proper dosing or to identify dosing errors. Incorrect events
may in some cases be disregarded or may be noted in the memory as
well, preferably with a suitable notation regarding their
incorrectness, also for use by the health care professional The
correct and incorrect opening and closing information can also be
used on an interactive basis such as to modify the dosing regimen,
to send signals to the patient or the health care professional
alerting them of changes or deviations from the desired or expected
regimen or the like.
Although not intended as a limitation on the structure of the
device in which the present time filtering is employed, the device
of FIGS. 1 and 2 can have several other useful features. These
features, which find application in other drug compliance monitors,
as well, are shown in FIGS. 4 through 7.
One such advantageous feature is to have a construction which
separates the drug from the electronics of the medication event
monitor. If the drug and electronics are allowed to come into
contact with one another the drug may interfere with the
electronics or the electronics may contaminate the drug such as by
releasing noxious or toxic materials into the drugs. In the
embodiment shown in FIGS. 4-6 the electronics are isolated in the
cap of the drug dispenser. In this embodiment the cap 12 includes a
cap body 41 having a continuous barrier 42. Barrier 42 has holes 43
and 43a through which electronic wires can be passed. The
electronics employed in the device, save and except for a single
switch 46 which is physically activated when the cap is removed or
replaced on the drug container, are carried on a printed circuit
board 45 which fits into body 41. Cap liner 48 is present shielding
the switch 46 from the drug storage region. When the cap is placed
on the drug container, the top lip of the container presses against
the liner 48 and forces it upwards against the switch 46 causing it
to open or close. The two leads on switch 46 pass through holes 43
and 43a and seal these holes, preferably so that there is no
possible contact between the drug contained in the device with the
electronics. A cap lid 49 is present covering the electronics. It
is overlaid with a label 50 which can carry information about the
drug, the device or the like.
Another useful feature of the device of this invention when
configured as shown in FIGS. 4-5 is the ability to recycle
electronics. The electronic circuitry employed in the present
invention is relatively costly as it contains at least one general
purpose microprocessor chip. While it is generally not preferred to
reuse drug containers for a sequence of drugs, for fear of some
risk or cross contamination, no matter how remote, it would be
desirable to recycle the electronics. In the configuration shown,
the single switch 46 can be uncoupled by removing two connections
and then the entire electronics board, which has not been in
contact with drug, can be removed and recycled.
Yet an additional feature of this preferred embodiment is shown
with special reference to FIGS. 6 and 7. This feature relates to
the way data is extracted from the memory of the device and
programs are fed into the memory of the device. One typical way to
do this is to use a telephone jack or the like. A preferred method
is shown in the figures where a simpler less space consumptive
coupling is shown. In this embodiment the coupling is effected
through a plurality of electrically conductive pads 51, 51a, 51b,
etc. these are aligned with a corresponding plurality of holes 52,
52a, 52b, etc in the cap lid 49. They also correspond in position
to a plurality of spring-loaded pins 54, 54a, 54b, etc in a data
probe 55. In use, the pins are thrust through the label 50, through
the holes 52 until the sharp ends of the pins 54 contact the
conductive pads 51. The pin 54 is loaded with spring 56 and held in
place by stop 57 so that a firm engagement between the pin and the
pad is possible. Conductor 58 carries data from the devices memory
or feed program to the device, as appropriate. FIG. 7 shows a top
view of one form of hole arrangement. In the arrangement shown,
there are 5 holes, arranged i a configuration which allows only a
single orientation of coupling of the connector. These five holes
are located in a particular position relative to registration mark
59. In actual use, the cap could be placed in an automated reader
of some sort with registration mark 59 properly aligned with a
corresponding position in the reader. Then the test pins 54 could
automatically align with and access the conductive pads through
holes 52. This configuration has the advantages of small size, and
low cost.
While the invention has been described with reference being made to
certain preferred embodiments, these are not to be construed as
limitations on the scope of the invention which is instead as
defined by the following claims.
* * * * *